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Finding the Fourth Proportional to 138.21, 206.33 and 115.08

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Solution

The fourth proportional to 138.21, 206.33 and 115.08 is: 171.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.21 : 206.33 = 115.08 : x
  2. Step 2: Convert to fraction form
    138.21/206.33 = 115.08/x
  3. Step 3: Cross multiply
    138.21x = 206.33 × 115.08
  4. Step 4: Simplify right side
    138.21x = 23,744.46
  5. Step 5: Solve for x
    x = 23,744.46/138.21
  6. Step 6: Final answer
    x = 171.80

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.